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New frontier with Laser spectroscopy of Muonium
Okayama University
RikenA, The University of British ColumbiaB,
KEKC, Peking UniversityD
Satoshi UetakeKoji Yoshimura
Collaborators:T. Hiraki, H. Hara, Y. Imai, K. IshidaA, S.
KamalB, N. KawamuraC, Y. MaoD, T. Masuda, T. MibeC, Y. MiyakeC, Y.
Miyamoto, M. OtaniC, K. ShimomuraC,K. SuzukiC, T. YamazakiC, M.
YoshidaC, K. Yoshimura, M. Yoshimura, C. ZhangD
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Introduction to Okayama University Group Brief introduction of
the SPAN project Macro-coherent amplificationFundamental Physics
using Hydrogen-like atoms History and present of Hydrogen
spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S
Laser Spectroscopy project at J-PARC Motivation and goal Project
overview and time schedule Recent status: simulation study and
hydrogen testFuture prospects High brightness muon source by 1S-2S
ionization of Mu High power 244 nm laser systemSummary
Outline
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Okayama-U Group
・Particle physics, Cosmology・Atomic/Molecular/Optical
Phys・Nuclear Physics・Physical chemistry
K. Yoshimura, M. Yoshimura, N. Sasao, T. Masuda, T. Hiraki, S.
Uetake, H. Hara, Y. Imai, K. Imamura, A. Yoshimi, Y.
MiyamotoStudents: K. Okai, H. Kaino, A. Fujieda, T. Kobayakawa, M.
Kobayashi, A. Gomi, H. Hiruma, S. Yamamoto
11 staff8 students
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SPAN: SPectroscopy with Atomic NeutrinoMeasure important
neutrino parameters using atoms/molecules Radiative Emission of
Neutrino Pair: RENP
「原子を用いたニュートリノ質量分光」, 高エネルギーニュース,33, 99 (2014)
β decay of 3H
18100 keV# of electron
Endpoint Spectrum
XeEnergy [eV]
0
8.315 18.6
0
Energy [keV]
−1−2E − 18.6 keV
(cf.)
Photon Energy [eV]
Rat
e [H
z]
1 2 3 4
Endpoint Spectrum
4.1565 4.1570 4.1575 eV
0.02
0.04
0.06
0.08
m0=1 meVm0=10 meVm0=50 meVNH/ IH
145 GHz
0
two-photonemission
RENP
−0.1Freq. [GHz]
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Neutrino Mass Spectroscopy with Atoms and LasersStimulate the
process with laser
Neutrino mass difference of 1 meV → Corresponds to freq. shift
of 100 MHzFrequency Resolution of Laser :
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Y. Miyamoto, SU, et al., Prog. Theor. Exp. Phys. 2015, 081C01
(2015)
Demonstration of Macro-Coherent Amplification
PPSLT LBO
CW864 nmECLD+TA
CW684 nmECLD
PPLN
Nd:YAG
Nd:YAG
SHG532
13864.59µm
4.59 µm
5.05 µm
684nm
532nm
LBO
KTA1064
p-H2
Damper
LPFs
Monochromator
MCTDetector
4.59 µm
5.05 µm
Coherence preparationwith Raman process
Two-photonis triggered with4.59 um laser
532 nm684 nm
(v = 1)
(v = 0)
Succeeded to Enhance E1×E1 two-photon emission rate : 1019
Gain
Macro coherent E1×M1 two-photon, three-photon emission;
solid-state target development
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Okayama-U group interests:Fundamental Physics using
state-of-the-art AMO technique → Manipulation of quantum state of
atoms/molecules by lasers
Application of Macro-coherent amplification to RENP
processDetail study of Electroweak to TeV scale physics in
Laboratory Determine yet unknown neutrino parameters (SPAN project)
Development of narrow/high-power laser system
340 nK~Tc
806040200
Num
ber o
f ato
ms
x103
40
20
0-60 -40 -20 0 20 40
Frequency [kHz]
~140 nK
goal
tool
Laser Spectroscopy of Bose-Einstein condensation(previous
work)
(AMO: Atomic/Molecular/Optical)
New!!Precision test of electroweak theoryby laser spectroscopy
of Muonium
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Introduction to Okayama University Group Brief introduction of
the SPAN project Macro-coherent amplificationFundamental Physics
using Hydrogen-like atoms History and present of Hydrogen
spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S
Laser Spectroscopy project at J-PARC Motivation and goal Project
overview and time schedule Recent status: simulation study and
hydrogen testFuture prospects High brightness muon source by 1S-2S
ionization of Mu High power 244 nm laser systemSummary
Outline
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Hydrogen-like Atoms: Simplest bound-system Precise theoretical
calculation is possible →Quantum Mechanics / QED development Energy
levels correspond to forces between positive/negative charge
Coulomb potential
Spectroscopy of One-Electron Atoms
1s1/21s1/2
2p1/2
2p3/22s1/2
n = 1
n = 2
1s
2s, 2p
Bohr Dirac QED
2s1/2, 2p1/2
2p3/2
……
potential ofCoulomb+new force
Electroweak
Hadronic effect
Compare Precise experiment / theoretical calculation↓
Precision test of electroweak theory may be possible
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1S-2S Laser Spectroscopy of Hydrogen
T. W. Hänsch, Nobel Lecture Slides (2005), with recent
results
1999: Optical frequency comb invention
1960: Laser invention
uncertainty [exp]: 11 Hz [1]
[1] Phys. Rev. Lett. 110, 230801 (2013)
T. W. Hänsch [theo] 44 kHz [2]
→due to proton structure (proton radius puzzle)3 order
discrepancy between exp & theory
[2] Eur. Phys. J. 172, 109 (2009)
Proton: compositparticle of 3 quarks
quark
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Hydrogen vs Pure leptonic systemH [Hydrogen (ep)] : lifetime
>1034 yrsBound system of Proton & Electron
Mu [Muonium (μ+e–)]:lifetime 2.2μsBound system of positive muon
& electron
lepton(=point charge)
quarklepton
Yes
NoLarge
Very Difficult
Composite particle of Hadrons and lepton
Components / Structure
only Leptons(point charges)
Precise theoreticalcalculation
Uncertainty fromNuclear structure
・QED・Electroweak・Found discrepancy between theo. & exp.?→May
be an evidence of Beyond the standard model (new Yukawa-type
potential)
Vacuum polarization(hadronic) +232.7(1.4) HzSov. J. Nucl. Phys.
53, 626(1991)
1st order Electroweak -65 HzPRA 53, 2953 (1996)
Ultra-precision Test
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A new scalar or vector boson coupled to electron and muon gives
rise to a Yukawa-type potential:
Constraints from astrophysics (e.g. stellar cooling effects) are
very strongNew physics search through Mu spectroscopy: Can be done
in a laboratory experiment Independent of a specific model
Spin-independent Dark Forces Spin-dependent Dark Forces
10- 13
10- 11
10- 9
10- 7
10- 5
10- 3
PresentMu 1S–2S(9.8 MHz)
Mu 1S–2S (10 kHz)
C. Frugiuele et al., Phys. Rev. D 100, 015010 (2019)
10-3 10-1 10110-510-18
10-16
10-14
10-12
10-10
10-8
10-6
10-4
10-2
100
10-8 10-6 10-4 10-2 100 102 104 106
Ps
HPresentMu 1S-HFS120 ppb
Mu 8 Hz
New physics New Physics
Constraints fromastrophysics
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Introduction to Okayama University Group Brief introduction of
the SPAN project Macro-coherent amplificationFundamental Physics
using Hydrogen-like atoms History and present of Hydrogen
spectroscopy Muonium spectroscopy and New physics Muonium 1S-2S
Laser Spectroscopy project at J-PARC Motivation and goal Project
overview and time schedule Recent status: simulation study and
hydrogen testFuture prospects High brightness muon source by 1S-2S
ionization of Mu High power 244 nm laser systemSummary
Outline
This project is funded byJSPS KAKENHI Grant-in-Aid for
Scientific Research (S) [FY2019-2023]S. Uetake (PI), K. Shimomura,
M. Yoshida, T. Yamazaki, M. Yoshimura
About to submit S type research project of J-PARC MLF
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Mu Energy Level
Present Precision and Our Goal
Laser Spectroscopy
mass uncertaintymass uncertainty
ppb: 10–9
mass
1S-2S Laser Spectroscopy
Microwave
mass
1S-HFS microwavespectroscopy
Uncertainty u[ ]Theo. : 1.4 MHz(comes from mass uncertainty of
120 ppb)
Uncertainty u[ ]Theo. : 515 Hz [2](comes from mass uncertainty
of 120ppb)
Electroweak Frequency shift: -65 Hz[2] M. I. Eides, Phys. Lett.
B 795, 113 (2019)
1S-2S Goalu[ ]exp.: 10 kHz(RAL 1999: 9.8 MHz[1])
Goal (a) : 1S-2S SpectroscopyReduce the mass uncertainty
120 ppb 1 ppb
11 Hz
[1] V. Meyer et al., PRL 84, 1136 (2000)
MuSEUM Goalu[ ]exp.: 8 Hz(LAMPF1998: 53 Hz)
Goal (b) :1S-HFS SpectroscopyPrecision Test of EW Theory
&
Search BSM physics
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Latest 1S-2S measurement (@Rutherford Appleton Laboratory,
1999)VOLUME 84, NUMBER 6 P H Y S I C A L R E V I E W L E T T E R S
7 FEBRUARY 2000
Measurement of the 1s-2s Energy Interval in Muonium
V. Meyer,1 S. N. Bagayev,5 P. E. G. Baird,2 P. Bakule,2 M. G.
Boshier,4 A. Breitrück,1 S. L. Cornish,2 S. Dychkov,5G. H. Eaton,3
A. Grossmann,1 D. Hübl,1 V. W. Hughes,6 K. Jungmann,1 I. C. Lane,2
Yi-Wei Liu,2 D. Lucas,2
Y. Matyugin,5 J. Merkel,1 G. zu Putlitz,1 I. Reinhard,1 P. G. H.
Sandars,2 R. Santra,1 P. V. Schmidt,1 C. A. Scott,3W. T. Toner,2 M.
Towrie,3 K. Träger,1 L. Willmann,1 and V. Yakhontov1
p.1136
Retroreflector!µ+
AlexandriteLaser
VacuumApparatus
Tripler Fast BeamDiagnostics
Cavity ControlElectronics
MCP
732 nm244 nm
Uncerntainty from ResidualDoppler → 3.4 MHzPulse laser was
usedlinewidth ~ 10 MHz
0
0.2
0.4
0.6
0.8
1
1.2
1.4
640 660 680 700 720νLaser-νIodine [MHz]
Even
ts p
er L
aser
Pul
se [1
0-4 ]
MuoniumF=1 → F=1
Signal
Theory
~20 MHz
Previous Muonium Laser Spectroscopy
No sophisticated optical frequency measurement technique
available# of μ:105μ+ /s; # of Mu in interaction region:1.5
/pulse
Results:2 455 528 941.0(9.8) MHz
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1S-2S Laser Spectroscopy Plan: Overview
2009 2012 2017 2020
Worldʼs highest intensity pulsed muon beam source108 µ/s beam
will be available from 2020
★
Phase 1 (uncertainty 1 MHz, ~Mar. 2021):S2 area (Starts from
2020B)Phase 2 (uncertainty 10 kHz, ~Mar. 2024):S2 area and H1
area
# of muon
x14
RAL1999
J-PARC MLF
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1S-2S Laser Spectroscopy Plan: Overview
2009 2012 2017 2020
Worldʼs highest intensity pulsed muon beam source108 µ/s beam
will be available from 2020
★
Phase 1 (uncertainty 1 MHz, ~Mar. 2021):S2 area (Starts from
2020B)Phase 2 (uncertainty 10 kHz, ~Mar. 2024):S2 area and H1
area
# of muon
x14
RAL1999
J-PARC MLF
G. A. Beer et al., Prog. Theor. Exp. Phys. 2014, 091C01
Efficient muonium production by Silica aerogel
Total Mu yield: 3%0
500
1000
1500
2000
2500
3000
Region 110 < z < 20 (mm) # of muonium
(in laser volume):RAL1999 1.5 /pulseH-Line ~104 /pulse
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1S-2S Laser Spectroscopy Plan: Overview
Aerogel
Surfacemuon beam
244 nm opticalcavity
SOAlens
LensElectrostaticmirror
Bending magnet
scintillator
MCP
Frequency stabilizationOptical fiber comb
Laser diode976 nmcw, 30 mW
SHG2.4W@488nm
FHG0.5W@244nm
Ionization355nm Nd:YAG
Fiber AmplifierNarrow-linewidth Laser system
2S Muonium Detection 244 nm244 nm355 nmIonization
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1S-2S Laser Spectroscopy Plan: OverviewTime schedule
Develop CW High-power 244nm laser
S2 area preparation@J-PARC
Phase 2 exp10 kHz uncertaintywith slow-MumeasurementPrecise
measurementof muon mass
Low-emittance muonsource via 1S-2S ionization(g-2 exp., Mu BEC
etc.)
Low-TempSlow-muonium
R&D
Develop 244nmpulse laser system
Test exp. with HFY 2019 FY 2020 FY2021 FY2022~
Phase 0 experimentDetection system testby pulsed laser
ionizationof Muonium
Phase 1 exp.Laser spectroscopyby narrow-linewidthlaser1 MHz
uncertainty
High-powerpulse laser
High-powerCW laser
RAL 1999Phase 1(2 years)
Phase 2(5 years)
µ+ intensity 1.8x105 cps 6x106 cps
(S line)1x108 cps
(H line)
Mu yield 6x102 cps 6x104 cps 1x106 cps
Laser Pulsed CW 10W CW 40W
Exp. Linewidth 20 MHz ~10 MHz ~0.5 MHz
Stat. uncertainty 9.1 MHz
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Simulation Study of 1S-2S ExcitationExpected resonance curves
are calculated in three steps: Surface muon beam distribution (by
G4beamline) Mu generation and tracking in thermal diffusion model
by MC 1S-2S excitation is described by optical-Bloch equation
Excitation probability is obtained by solving optical-Bloch
equation for each muonium diffused from silica aerogel
Visit Poster PN-06 by C. Zhang MLFPN-10 by T. Masuda
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Develop whole detection system usinghydrogen spectroscopy
apparatus
Test Experiment with Hydrogen
resonant 2-photonionization signal
Hydrogen
243 nm
243 nm
Muonium
244 nm
244 nm
[H generation]2.45 GHz Microwavedischarge
Discharge ON
Discharge OFF
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Introduction to Okayama University Group Brief introduction of
the SPAN project Macro-coherent amplificationFundamental Physics
using Hydrogen-like atoms History and present of Hydrogen
spectroscopy Muonium spectroscopy and New physics1S-2S Laser
Spectroscopy project at J-PARC Motivation and goal Project overview
and time schedule Recent status: simulation study and hydrogen
testFuture prospects High brightness muon source by 1S-2S
ionization of Mu High power 244 nm laser systemSummary
Outline
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High Brightness Muon Production
Present beam: target(e.g. μSR )
target
emittance~1000� mm∙mrad
Proton
π production
decay
Future application of the Phase 0 experiment (1S-2S
ionization)
1S-2S Laserionization@244 nm
Alternative to the on-goingLyman-α ionization @122 nm
Silicaaerogel
SOA Lens
High brightnessmuon beam
Difficultto focus
>20 mm
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Conventional technique
Collaborating with M. Yoshida (KEK)
Conventional technique
Developing forphase 0 exp.
New!High-Power 244 nm Laser Source
Ti:Scrystal
Pump
CW laser SOA
arb. form pulse~30mW976 nm ~30mW×1μs→30 nJ
~600 mJpulse
x N stageamplifier
SHG400mJ
@488nm
FHG200mJ
@244nm
Similar Yb:YAG multi-pass amplifier system developed at KEK
Developing 244 nm high power laser is much easier than
developing Lyman-α
Conventional technique can be usedEasy handling (air is
transparent at 244 nm, while Lyman-α is strongly absorbed)
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Similar ionization fraction→may become a good
alternative of Lyman-α
1S-2S Laser Ionization of Muonium
Wavelength PowerIonization
fraction81,946 Mu tot.
Lyman-α 122 nm (VUV) 3 μJ 3.0%
1S-2S REMPI 244 nm 200 mJ 1.6%
1S-2S ionization →
↑ Lyman-α ionization
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The goal of this project:Realize the highest precision by use of
state-of-the-art technologies developed in AMO physics (Ultrafine
laser spectroscopy) Particle/Nuclear physics (High intensity
accelerator)
1S-2S Laserspectroscopy
Accelerator technologies
Muon g-2
MuSEUM
Precision test of electroweak theory and search for new physics
beyond the Standard Model
by laser spectroscopy of purely leptonic atoms
Precision EW test
JSPS KAKENHI Grant-in-Aid for Scientific Research (S)
[FY2019-2023]
interdisciplinaryresearch project
High power laserLaser ionizationMu production